. >>> and a north bay oyster company is fighting an eviction order by the federal government. a 40-year agreement between the park service and drinks bay oyster company expired last month. the park service says the company's operations threaten endangered species in the area. but now the owners have filed a complaint in court saying the interior department's denial of a permit extension violates federal law. but meanwhile, oysters are turning up in a surprisingly new place. >> about a hundred of them were discovered in the vallejo municipal arena. as don ford tells us, it is a sign the ecosystem there is starting to recover. >> reporter: the city of vallejo was dredging their public marina when they dug something up. something no one expected. something odd, says marina manager. >> i've been here since 23 years and i've never seen these guys before. >> reporter: california oysters. although small and not too many, these oysters are sensitive to water quality. folks here believe it's a good sign. >> obviously, the water's getting better. quality's getting much improved, which i